Haven't driven US-64 between Raton and Cimarron, but haven driven from Cimarron to Taos many times. There is a pretty steep climb through Cimarron Canyon to Eagles Nest and Angel Fire. From there there is another climb to about 9,000' before descending into Taos. Both sections have areas of 35MPH speed limits, narrow shoulders and lower speed turns.
Haven't driven all of the route from US-160 South, but NM-522 from the Colorado border to Taos is a pretty good road. Lots of ups and downs but no really steep sections with tight turns.